Assume that technology comes into place to store all banking data in Secret Swiss bank accounts, and that it becomes easy and practical to access these accounts every time that a purchase is made. Now, what is stopping people from making every purchase ‘unofficially’, not reporting it to the government, and making it thus untaxable?
Now, how would the government react to such a change in the social order? Would people pay things like sales and income tax out of fear? Civic duty? Laziness?
Now, the tough questions: Does the government have a right to a bit of every purchase you make? How much you are paid?